Chemistry Sim · Atomic Structure
Add protons, neutrons, and electrons and watch your atom take shape. Discover the element, its mass, its charge, and whether you've built an ion or an isotope.
The nucleus holds protons (pink) and neutrons (blue). Electrons (teal) orbit in shells.
Add or remove subatomic particles and observe what changes.
Protons determine the element. Changing this changes everything.
Different neutron count = isotope of the same element.
Unequal electrons and protons = an ion.
The number of protons is called the atomic number. Every carbon atom has exactly 6 protons; every oxygen atom has 8. Change the proton count and you change the element itself — and its chemical identity.
An isotope has the usual number of protons but a different number of neutrons. An ion has an unequal number of protons and electrons, giving it a positive or negative charge. Both are still the same element.
Check yourself